The past decade has been marked by a technological revolution driven by the convergence of the data processing industry with the consumer electronics industry. An area where this relationship has been advantageous is that of digital video recording. A variety of digital recording devices have become the standard for video recording for the present generation. Digital audio/video recording has many advantages, including the ability to randomly access any portion of the digitally recorded content, higher definition video displays and longer storage life. This has resulted in the compact optical digital recording disc emerging as the standard for recording in the video and audio consumer electronic fields, and the advancement of the CD and DVD for their use as text and other books on disc that may be read by the consumer on a basic laptop computer. Books on disc are making great strides in relieving students of the “fifty-pound” book bags on college campuses.
Because of the extensive use and prominence of these digital recording discs, there has arisen a need to enable the user to record his personalization data in relation to a compact digital disc or a set of such discs in order to annotate and organize the discs. Until now, the user had to separately record any data that was ancillary to such compact discs on a computer that supported the compact digital discs. Since the compact digital discs (either CDs or DVDs) that contained the recordings of videos, audios, films or books, were read-only permanent digital recordings, such user personalization data could not be recorded on the discs. This created the rather cumbersome situation in which the discs had to be used in association with the computers that contained the personalization and disc organization data in order to get the benefit of such ancillary data.
The present invention provides one solution for such conditions. However, before considering the solution provided by this invention, we should review some CD and DVD background. A very thorough history and background of structures and manufacturing processes of both CD and DVD types of digital optically recorded discs may be found in the text: DVDs Demystified, by Jim Taylor, published by McGraw-Hill Professional Publishing, 2000/01. The basic CD (Compact Disc) is an injection molded piece of clear polycarbonate plastic material. The molded plastic is impressed with minute microscopic bumps arranged in a very long spiral track that is continuous and extends from the center of the disc. A thin layer of reflective aluminum is then sputtered onto the disc that covers the track of bumps and the aluminum is then covered with a thin layer of clear plastic. This provides a read-only spiral bump pattern on the track of reflective aluminum that may then be read by a reflective laser beam in the CD player to produce a digital output that is then suitably amplified to provide a digital display or audio output, or if an analog output device is used, then the output is applied to a D to A converter and then used for the video or audio output.
DVDs generally have the same diameter and thickness as CDs and are manufactured by similar methods, but the DVD has up to four layers of aluminum covered reflective bumps, with each layer being produced by a separate process in which a single metal covered layer of bumps is used. Using laser beam reading there may be two such layers of spiral bump tracks on each side of the optical disc. Consequently, for the high recording density four layer DVDs, there could be two layers on each side of the disc. In such two layer to a disc side structures, an aluminum layer is sputtered behind the inner layers as the reflective laser readable layer. A semi-reflective layer is used for the outer layers that allows the laser beam to focus through the outer layer onto the inner layer. Thus, the laser beam may be appropriately focused to read the spiral track on either layer.
Both the DVDs and CDs used for audio and video in commercial electronics, as well as for books on discs, are permanent read-only digital recordings.